For now, we prefer keeping with our tradition and releasing missions which are not "similar to" - on the contrary, we're looking for missions which are unique in some way. Eventually however we'll run out of them and reach the missions you mention. Then it is likely that we can reuse many of the mission elements we've developed already for the previous "unique" missions. Even today, ISS missions are more or less routine for us as we already have most if not all of the necessary elements in place. Ares was developed from the ground up, and in record time, considering that we had to build all the content from scratch, and add something we never had before - namely, the splasdhown. Now, that element is available for eventual inclusion into the STS launches, so Ares has not been a complete waste of resources after all
Now, most of the effort goes for developing the next release of the Space Shuttle Mission. With it will come new major features - many from the Suggestions board, and from our own roadmap, and of course, new, cool and "unique" missions.
We hope that most of you will like the ride. We know we do.
/Admin